1. Technical Field
This invention relates to methods of treating neuro-olfactory triggered or related or exacerbated conditions in general, and to methods of temporarily and safely disabling and/or inhibiting a subject's sense of smell in particular.
2. Background Information
Many physical conditions are known to be triggered or caused in whole, or in part, or aggravated by a neuro-olfactory response to an odorant or irritant chemical (hereinafter referred to as an odorant or an odor), or chemicals sensed by the olfactory receptors of a subject. Such conditions (sometimes referred to as “disorders”) can include one or more of multiple chemical sensitivity, somatoform disorder, chronic fatigue syndrome, fibromyalgia, panic disorder, autism, epilepsy, asthma and post-traumatic stress disorder in which afflicted individuals have may hypersensitivity to chemical odorants. For instance, panic attacks have been shown to be triggered by certain odorants in susceptible individuals. Over-eating habits that lead to obesity also have a complex, not yet completely understood, neuro-olfactory components.
Multiple Chemical Sensitivity (MCS) is one example of a disorder, or constellation of disorders, that causes certain individuals to have multi-organ symptoms in response to low-level chemical exposures that are considered safe for the general population. Individuals with MCS may experience a large catalogue of debilitating symptoms after an exposure to certain chemical substances. Examples of debilitating symptoms include the following: a) neurologic symptoms including headache, fatigue, irritability, cognitive dysfunction, decreased attention span, loss of concentration and memory, dizziness, loss of motivation, confusion, sleep disturbances, anxiety, depression, mood swings, neurasthenia, numbness, hyperactivity, shortness of breath, tingling/numbness in fingers/toes; b) cardiovascular symptoms including palpitations, irregular heartbeat, etc.; c) respiratory symptoms including dyspnea, cough, chest pain and tightness, shortness of breath, rhinorrhea, nasal and eye burning, pharyngeal irritation; d) gastrointestinal symptoms include dyspepsia, diarrhea, nausea; e) genitourinary symptoms including dysmenorrhea, urinary frequency, ovarian cysts; f) musculoskeletal symptoms including myalgia, weakness, muscle tension, arthralgia, dyskinesia; and g) dermatologic symptoms including skin irritation.
The degree of sensitivity to each odorant or irritant chemical varies with each individual with MCS, but a general, but non-comprehensive, list of problem odorants and irritant chemicals that includes: solvents, pesticides, combustion products of gas, oil, and coal, fresh paint, turpentine, mineral spirits, fertilizers, perfumes, cosmetics, nail polish, cleaning products, air fresheners, cigarette smoke, carpet, adhesives, building materials, automobile and diesel exhaust, roof and road tar, industrial air pollutants, chemical preservatives (sulfur, sweetening agents), chlorine in water, medications, synthetic textiles, copy machines, and laser printers. The prevalence of this disorder in the United States is believed to be between 0.2% and 6% of the population, with 4% being an often-cited figure. In one study, Silberschmidt reports that thirty percent (30%) of all Swedish housepainters were shown to have MCS. Approximately thirty percent (30%) of the entire population experiences some low-level, but often debilitating, response to aggravating chemicals.
While the etiology of MCS is not known, it is generally felt to be triggered by the olfactory stimulation either by odor or irritant of the olfactory receptors, and subsequent stimulation of the limbic system, and or other areas of the brain resulting in the complex and varied symptoms known to be manifestations of the MCS. Some experts believe that a psychological conditioning response to odors that previously triggered an adverse reaction in the individual plays a role in the overall causal mechanism for MCS. The condition MCS is assumed to be developed in two steps: a) an initial phase with exposure often to a high concentration of a chemical substance; and b) a trigger phase, which is the subsequent set off of a number of symptoms by exposure to low concentrations of chemicals. Researchers have shown that, in a kind of compounded Pavlovian response, when an individual is experiencing adverse affects from one chemical, other inhaled chemical odorants that are in proximity to the individual at the time, may be added to the triggering odorants. The number of chemicals that a MCS individual are sensitive to may increase exponentially in this manner.
While avoidance of exposure to all manner of neuro-olfactory triggers is typically the prescribed course of action, this strategy is obviously difficult, if not impossible, to carry out. Perfumes, personal fragrances, paints, aerosol sprays, indoor carpets, household cleaners, pollutant from building materials and mattresses are a small sample of the routine chemicals encountered daily which may make a neuro-olfactory sensitive person (e.g., someone who suffers from MCS) seriously ill. Such illnesses often greatly limit a subject's ability to work, shop, travel, and socialize. Many subjects become homebound due to their illness. The illness can be severely disabling to the patient and costly to society.
Another neuro-olfactory triggered condition is the common reaction of nausea and or disgust upon exposure to the odorants associated with rotten flesh or food, especially protein containing foods, feces, anaerobic infections and other pathophysiologic substances such as vomitus, body discharges, and infection related exudates. While the reaction to these odors is probably determined in part by evolutionary means, and is beneficial in that the subject should not eat those substances or avoid exposure to substances emanating those odors, it is sometimes not possible to avoid them as in the case of care givers, health service personnel, and first responders. In such cases, it would be desirable to provide a methodology that enables avoidance of normal physiologic response or sensation or discomfort engendered by the exposure to such odorants. For purposes of this document such conditions shall be referred to by the term “Neuro-Olfactory Triggered or Aggravated or Related Conditions”.
Obesity is another condition or illness attributable to complex genetic, environmental and social causes where the condition is associated with an exposure to an odorant, and where the normal, usually beneficial, physiologic response may lead to an undesired outcome—obesity. People are aware of increased appetite after exposure to pleasant food odors as well as the Pavlovian increase in saliva, stomach acid and intestinal motility—all beneficial—except when a propensity to obesity exists, and the subject overeats. It is known in the prior art to use strong pharmacologic agents such as sodium and calcium ion channel blockers, vasoconstrictors, as well as anticholinergic drugs such as atropine and local anesthetics to induce temporary anosmia. All of the aforementioned active pharmacologic agents have significant side effects, and known toxicity rendering them subject to careful medical supervision as well as regulatory supervision by the United States FDA, or other supervisory agency appropriate to the geographic location. Over dosage with these drugs may result in serious illness or even death.
In the previously described conditions the subject must determine the need for avoidance of stimulation by the odorant, and this determination is therefore appropriately labeled as completely subjective. This dependence upon the subjects' perceived need renders the use of potentially dangerous pharmacologic agents unwise and unsafe since the needed frequency of administration depends upon many variable factors, and may result in toxicity if the potentially toxic drugs present in the agent are applied too frequently. The factors affecting the needed frequency of administration of an agent that will induce temporary anosmia/hyposmia include, but are not limited to: a) the concentration of the odorant; b) the ability of the subject to avoid continued exposure; c) the sensitivity of the chemosensors of the olfactory sensors to the odorants; d) the solubility of the odorant in the layer of mucus overlaying the nasal olfactory sensors; and e) the thickness and viscosity of the mucous layer overlaying the sensors (since the odorant must diffuse through that layer to reach the sensor to be perceived, and to initiate and/or trigger the undesired response.)